Composite Materials and Mechanics Laboratory, Mechanical and Aerospace Engineering Department, Polytechnic Institute of New York University, 6 MetroTech Center, Brooklyn, NY 11201, USA.
J Biomech. 2010 Nov 16;43(15):3044-50. doi: 10.1016/j.jbiomech.2010.06.034. Epub 2010 Jul 31.
Strain rate dependence of the mechanical response of hard tissues has led to a keen interest in their dynamic properties. The current study attempts to understand the high strain rate characteristics of rabbit femur bones. The testing was conducted using a split-Hopkinson pressure bar equipped with a high speed imaging system to capture the fracture patterns. The bones were also characterized under quasi-static compression to enable comparison with the high strain rate results. The quasi-static compressive moduli of the epiphyseal and diaphyseal regions were measured to be in the range of 2-3 and 5-7GPa, respectively. Under high strain rate loading conditions the modulus is observed to increase with strain rate and attains values as high as 15GPa for epiphyseal and 30GPa for diaphyseal regions of the femur. The strength at high strain rate was measured to be about twice the quasi-static strength value. A large number of small cracks initiated on the specimen surface close to the incident bar. Coalescence of crack branches leading to fewer large cracks resulted in specimen fragmentation. In comparison, the quasi-static failure was due to shear cracking.
骨组织的力学响应的应变速率依赖性使得人们对其动态特性产生了浓厚的兴趣。本研究试图了解兔股骨的高应变率特性。测试使用配备高速成像系统的分离式 Hopkinson 压杆进行，以捕捉断裂模式。还对骨骼进行了准静态压缩特性测试，以便与高应变率结果进行比较。骺端和骨干区域的准静态压缩模量分别测量为 2-3GPa 和 5-7GPa。在高应变率加载条件下，观察到模量随应变速率而增加，并在骺端区域达到高达 15GPa，在骨干区域达到 30GPa 的值。高应变率下的强度测量值约为准静态强度值的两倍。大量小裂纹在靠近入射杆的试样表面上萌生。裂纹分支的合并导致较少的大裂纹，从而导致试样破碎。相比之下，准静态失效是由于剪切裂纹引起的。
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